kubecon25/content/day-2/10_auto-scale.md
Nicolai Ort 3e4fbb616b
All checks were successful
Build latest image / build-container (push) Successful in 53s
docs(cnrj): Added video links
2025-04-03 10:59:24 +02:00

73 lines
1.8 KiB
Markdown

---
title: "The auto-scaling part: VPA, HPQ, KEDA, Nodes, How do they dance"
weight: 10
tags:
- rejekts
---
{{% button href="https://www.youtube.com/watch?v=1US_-3udMDo" style="warning" icon="video" %}}Watch talk on YouTube{{% /button %}}
<!-- {{% button href="https://docs.google.com/presentation/d/1nEK0CVC_yQgIDqwsdh-PRihB6dc9RyT-" style="tip" icon="person-chalkboard" %}}Slides{{% /button %}} -->
## Hypothesis
- In 2024 27% of cloud spent was wasted
- 100ms delay => decrease in sales
## Pod resources
- Requests: Informs scheduler's decision
- Too low: Schedule on strained nodes
- Too high: Wasted resources
- Limits: Throttels (CPU) or Kills (Memory) if reached
- QoS: sort the eviction priority during ressource pressure
- Quranteed (request=limits)
- Burstable (Limits>Requests)
- Best effort (Nothing defined)
- Gotcha: CPU throtteling can happen before tirggers happen if requests and limits are very close
TODO: Steal table from Slides
Requests | 100m, 256Mi | 100m, 256Mi
Limits |100m, 256Mi | None or <limits
QoS | Gurantee | Burstable | Best effort
## Scalers
- VPA: Moar power aka reccomend requests
- HPA: Moar moar aka more replicas
- KEDA: Proxy over HPA
### VPA
Modes:
- Off: Dry-Run
- Initial: Applies Reccomendations to new Pods (can be used for finding out)
- Auto/Recreate: Evicts and restarts pods to update resources
Trigger: Usually Memory
Tip: `maxAllowed` in order to not exhaust stuff
### HPA
- Trigger: Usually cpu (percent of requests)
- Formula: $1+\frac{usage}{target}$
- Fun fact: Can not scale to 0
### KeDA
- Basicly automates HPA with flexible metrics (from different soruces)
- Can scale Jobs
- Can Scale to 0
## Anti patterns
TODO: Steal from slides
| Pattern | Bad | Better
| CPI limit = Requests | Throtteling before scale | Set requests only |
## Demo
Auto scaling meme generator (see slides/video)